Buck knives sharpening system. Triangular, has 3 different grits for finish. Side 1 coarse diamond stone,  side 2 fine diamond stone, side 3 is fine natural stone. Great easy system, has had very little use.  SMITH'S COMPANYS VERSION OF THIS, 6IN. DIAMOND SHARPENER AT CABELLAS IS $59.95      WILL SHIP ON YOUR DIME. CALL OR TEXT ONLY, WILL NOT REPLY TO E-MAIL [TOO MANY SCAM E-MAILS]   THANKS FOR LOOKING    REDACTED   PHIL